docs: def distances():
    """
    Get all distances between all cities in miles (matrix-style). 
  
    Returns:
      dictionary of Backpage city names mapped to a list of distances, one for every other city
    """
    distances = {}
    # Instantiate a matrix of distances (in miles) between all cities
    num = 0
    top_row = 1
    fname = pkg_resources.resource_filename(__name__, 'resources/Distance_Matrix.csv')
    with open(fname, 'rU') as csvfile:
      reader = csv.reader(csvfile, delimiter = ',')
      for row in reader:
        if top_row == 1:
          top_row = 0
        else:
          # Map each city to a list of distances to all other cities.
          vals = []
          for item in row[1:]:
            if not item:
              continue
            try:
              vals.append(int(float(item)))
            except ValueError:
              print 'Invalid data type for row {} with value {}, column value: {}'.format(num, row[0], item)
          distances[num] = vals
          num += 1
  
    return distances